NTP Nanotechnology Safety Initiative

Nanotechnology is defined by the National Nanotechnology Initiative (NNI) as "the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable novel applications." These materials can, in theory, be engineered from nearly any chemical substance; semiconductor nanocrystals, organic dendrimers, and carbon fullerenes and carbon nanotubes are a few of the many examples. Nanoscale materials are already appearing in commerce as industrial and consumer products and as novel drug delivery formulations. Commercial applications and resultant opportunities for human exposure may differ substantially for "nanoscale" compared with "bulk" materials.

There is very little research focus on the potential toxicity of manufactured nanoscale materials. The unique and diverse physicochemical properties of nanoscale materials suggest that toxicological properties may differ from materials of similar composition but larger size.

Surface properties can be changed by coating nanoscale particles with different materials, but surface chemistry also is influenced by the size of the particle. This interaction of surface area and particle composition in eliciting biological responses adds an extra dimension of complexity in evaluating potential adverse events that may result from exposure to these materials.

NTP is engaged in a broad-based research program to address potential human health hazards associated with the manufacture and use of nanoscale materials. This initiative is driven by the intense current and anticipated future research and development focus on nanotechnology. The goal of this research program is to evaluate the toxicological properties of major nanoscale materials classes which represent a cross-section of composition, size, surface coatings, and physicochemical properties, and use these as model systems to investigate fundamental questions concerning if and how nanoscale materials can interact with biological systems.